The present invention relates to a process for preparing sorbic acid, and more particularly to a process for preparing sorbic acid by microbiologically oxidizing sorbic aldehyde.
Sorbic acid and its salts have been preferably used as preservatives for foods because of their excellent antifungal activity. Sorbic acid has been industrially prepared by, ususally, reacting crotonaldehyde with a ketene to give a polyester through .alpha.-lactone produced as an intermediate, and decomposing the polyester with heat or an acid, or by using an ion exchange resin.
However, the above-mentioned process is not always advantageous in preparation and economy, that is, the recovering or purifying operation of sorbic acid after decomposing the polyester is troublesome, many steps and the complicated process control are required.
Recently, for solving the above disadvantages, Japanese Unexamined Patent Publication No. 152990/1988 has proposed a method wherein sorbic aldehyde is treated with a specific microorganism such as Pseudomonas to prepare sorbic acid. However, when conducting the method in an industrial scale, still it has been disadvantegeous in yield.
An object of the present invention is to provide a process for preparing sorbic acid in high yield.
This and other objects of the present invention will become apparent from the description hereinafter.